Domain admin account locking in main AD controller

All time AD was used without password locking feature. After hacker intervention I set password expiration and account lock in AD group policy. Now I have a problem with my account. I'm AD administrator and my account is in Domain Admins group. NetWrix Account Lockout examiner show locking of my account periodically. All locking workstation name show 4 PCs - 3 of them are AD controllers and one Veeam backup server. Most often locks are from main AD controller on main AD controller.

No services or scheduled tasks started with my account on AD controllers.

I do not understand what to search in Event log of main AD controller. Where to find a problem?